5 ms·
Let's put it this way: if you attached a light bulb (which can get fairly hot) to USB, would you expect the same problem? What about plugging a soldering iron i
by pluma 11y ago
Let's put it this way: if you attached a light bulb (which can get fairly hot) to USB, would you expect the same problem? What about plugging a soldering iron in the wall plug -- would you expect that to heat the socket (and cable)?
It's not the current that makes it hot, it's how the current flows through it.
EDIT: It's basically about resistance (the things that get hot are the resistors): https://en.wikipedia.org/wiki/Electric_heating https://en.wikipedia.org/wiki/Electric_heating
EDIT2: I'm not an electronics person either. Please feel free to correct me if I'm grossly misrepresenting how things work.
- LeifCarrotson 11y agoAnd by "fairly hot", you might use as an example the tungsten filament in a Christmas light bulb - which can be 2500 C! Power (and therefore heat) is current squared times resistance, or equivalently voltage drop times current. A copper wire or PCB trace has very low resistance, and a soldering iron tip or thin tungsten filament has high resistance, so one stays cool while the other gets hot.
- collyw 11y agoOk, thanks for clearing it up. I had kind of assumed PCB trace would have some resistance due to the relatively small size of it (compared to say a cable on an electric appliance), but I guess the heat is coming from the soldering iron tip and doesn't need to be huge to get it hot.